Citation and License

Arthritis Research & Therapy 2011, 13:R167
doi:10.1186/ar3487

Published: 13 October 2011

Abstract

Introduction

Fatigue is prevalent in primary Sjögren's syndrome (pSS), and contributes to the considerably
reduced health related quality of life in this disease. The symptom is included in
proposed disease activity and outcome measures for pSS. Several studies indicate that
there is an inflammatory component of fatigue in pSS and other chronic inflammatory
rheumatic diseases. The purpose of this study was to investigate fatigue change in
pSS in a longitudinal study, and explore whether any clinical or laboratory variables
at baseline, including serum cytokines, were associated with a change in fatigue scores
over time.

Methods

A clinical and laboratory investigation of 141 patients fulfilling the American-European
consensus criteria of pSS was undertaken in the period May 2004 to April 2005. Median
time since diagnosis was 5.5 years. Examinations included the fatigue questionnaires:
fatigue severity scale (FSS), fatigue visual analogue scale (VAS), functional assessment
of chronic illness therapy - fatigue (FACIT-F) and medical outcome study short form-36
(SF-36) vitality, which were repeated in a follow-up investigation in January and
February 2010.

Results

A total of 122 patients (87%) responded at both time-points. Thirty-five percent of
patients experienced a clinically significant FSS increase. On the group level, fatigue
measures did not change except that there was a slight deterioration in SF-36 vitality
score. High serum anti-Sjögren's syndrome A antigen (anti-SSA) showed weak associations
with high baseline fatigue, and patients with increasing fatigue had lower baseline
unstimulated whole salivary volume. Weak associations between increasing fatigue and
serum immunoglobulin G (IgG), and the pro-inflammatory cytokine interleukin-17 (IL-17),
were observed. Baseline sicca symptoms correlated with higher fatigue both at baseline
and with increasing fatigue over time. Linear regression analysis did not identify
any predictive ability of clinical or laboratory measures on fatigue change over time.

Conclusions

Fatigue remained mainly unchanged over time. Using multivariate models did not reveal
any clinical or laboratory predictors of fatigue change over time.